Water

Safe SustainableAnd for all

Chennai – An Overview

Chennai district has tropical maritime monsoon The annual rainfall in Chennai is in the range of 1200 - 1300 mm On an average Chennai receives rainfall for 300 hours throughout the year The city receives more rainfall during north-east monsoon i.e., in the month

of October to December After the severe drought of 1992 & 1993 Metro Water began to take active

part in promoting rain water harvesting

The main sources of public water supply in the city are the three reservoirs - Poondi, Redhills and Cholavaram - with an aggregate storage capacity of 175 MCM.

Cost of metro water tanker 10kiloliters varies from 600-850 rupees depending on the type of occupation

At the peak of summer 2002 year, a 12,000 litre tanker of water cost as much as Rs 1,500 to Rs 2,000

there is a total of about 800 Kms length network of storm water drains in the city

2

0

200

400

600

800

1000

1200

1400

1600

2001 2011 2021

demandsupply

1070

1547

675

1327

675

971

MIllIon

L/day

Jan...1.2Feb...0.3Mar...0.2Apr...0.6May...1.5Jun...2.4Jul...3.9Aug...5.4Sep...4.8Oct...11.1Nov...14.0Dec...5.6

Average Monthly Rainfall in Chennai (in inches)

Water Requirements per person

Purpose Litres Per day Litres Per month

Litres Per year

Drinking 3 90 1080

Cooking 4 120 1440

Flushing 40 1200 14400

Bathing 20 600 7200

Washing clothes 25 750 9000

Washing Utensils

20 600 7200

Gardening 23 690 8280

Total 135 4050 48600

Grey water 65 1950 23400

4

Water Management System5

BORE WELL

/GREY WATER PIT

OVER HEAD TANK

• Bathing• Washing• Cleaning

Sources of Grey Water

SIDE STRAPPED TANK

CAN BE RECYCLED AND USED

Drinking

Cooking

Grey water Systems6

Grey water refers to the reuse of water drained from baths, showers, washing machines, and sinks (household wastewater excluding toilet wastes) for irrigation and other water conservation applications.

Existing Rain water Pit

The site consists of two floors with four dwelling units. The total number of people dwelling is 20.

The existing pit is of 2 feet X 2 feet X 30 dimension. This has the capacity of 3398 liters of water.

Total roof top area 60sqm Total consumption per day 2700 total grey water produced 1300liters per day 800 liters of grey can be reused to flush toilets

Site Analysis8

SOURCES OF WATER • RAIN WATER • BORE WATER• MUNICIPAL WATER

Building Layout 9Water harvested in the building with a flat terrace area of 60

sq .m The average annual rainfall in Chennai is approximately 1300mm. In simple terms, this means that if all the rain that falls on the terrace is retained, then in one year there will be rain water on the terrace floor to a height of 1300mm.Area of Terrace :60 sq. m.

Height of rainfall:1.30m (1300

mm)

Volume of rainfall over the TerraceAssuming that 90% of the total rainfall is effectively

harvested.Volume of water harvested = 78000x0.9 = 70200 liters

That means ( 70200 / 365 ~ ) 192 liters of water per day will be available for the household.

Water required per day 72L/PERSON portable water

Area x Height of Rainfall

60 sq. m. x 1.30 m

:78 cu. m. (78,000 liters)

Amount of water required per day ---20X135 = 2700L

Water reused [GREY WATER ---20X63 =1260

Hence the water harvested is insufficient and needs more of water management systems

Design Solutions & Benefits Water friendly building

design DESIGNING BUILDINGS FOR WATER Designing with buildings which are self contained with water storing

methods rather than filling up the house with water drums. The method used consists of two horizontal ferro cement pre cast units of

size 4m X 1m These units are present in each of the floors These units can be supported by the lintel beams of the existing building or

they can be supported by the floor slab the other options are floating columns.

Other materials like PVC pipes with large diameters can also be used as storage units

For good aesthetical appearance fiber glass can be used Making rain water 100% efficient by using rain water directly by connecting

tank to water closet and tapping it without even flushing the first rain Rain water which is not used for consumption directly can be used for non

portable

10

1.5m

1m

Area of the tank 1sqm

Height 1m

Volume 1000L OF WATER

Design12Merits

• Maximizing the water usage during rain

• Save electricity used to pump the water to the over head tank during rains by directly using water from these tanks

• During summer time this tank can be used to store geen water which is treated at the roof level

• Great aesthetical appearance since they can b designed as per the building styles

• Landscaping can be done over these to further improve the design

• Over head water tank over flow water can also be saved

• Do not occupy space or cause any hindrances like the water cans or drums since they are designed at the initial stages of planning depending on the water requirement

Design13

De Merits

• The tank is left unused in case there is no rainfall

• There will be 2 or 3 different plumbing lines

• if in case the tanks are used to store grey water during summer they must be cleaned and maintained well before the rain starts

• Water proofing must be done carefully else chances

Of water seepage into the walls

Design Solutions & Benefits14

For future projects

Sunken slab for grey water treatment landscape .

Size of tank to store 1000L of water

1mx2mx

15

References

www.akash-ganga-rwh.com

http://www.chennaimetrowater.tn.nic.in/rwh/rainwaterwhy.htm

www.rainwaterclub.org

http:/www.livingroofs.org/livingpages/

C.VISHNU PRIYA BHARATH INSTITUE OF HIGHER EDUCATION

AND RESEARCHc.vishnupriya@gmail.com